Function InsertPages() [from "AcroExch.PDDoc"] does not insert pages in VBA.

Hello guys,

I am new here. I wrote a simple code which needs to merge 2 PDF files.

Problem:

• The fucntion InsertPages() does not want to insert pages from another PDF file. 
• I am not getting any errors.
• I am always getting FALSE returned from InserPages().

Question:

• Does anybody have an idea?

As you can see, the code is super simple.

Sub mergePDFfiles()


    Dim Aapp As Acrobat.AcroApp
    Dim Doc01 As Acrobat.AcroPDDoc
    Dim Doc02 As Acrobat.AcroPDDoc
    Dim Doc03 As Acrobat.AcroPDDoc
    Set Aapp = CreateObject("AcroExch.App")
    Set Doc01 = CreateObject("AcroExch.PDDoc")
    Set Doc02 = CreateObject("AcroExch.PDDoc")
    Set Doc03 = CreateObject("AcroExch.PDDoc")
    
    Aapp.Show
    '------------------------
    Dim sName00, sName01, sName02, sName03 As String
    Dim sPfad00, sPfad01, sPfad02, sPfad03 As String
    Dim vAnzahl01, vAnzahl02, vAnzahl03 As Long
    sPfad00 = ThisWorkbook.Path + "\DocTOTAL.pdf"
    sPfad01 = ThisWorkbook.Path + "\Doc_01.pdf"
    sPfad02 = ThisWorkbook.Path + "\Doc_02.pdf"
    sPfad03 = ThisWorkbook.Path + "\Doc_03.pdf"
    If Doc01.Open(sPfad01) Then
        sName01 = Doc01.GetFileName()
        vAnzahl01 = Doc01.GetNumPages()
        MsgBox sName01 + " has " + CStr(vAnzahl01) + " pages and is open."
    End If
    If Doc02.Open(sPfad02) Then
        sName02 = Doc02.GetFileName()
        vAnzahl02 = Doc02.GetNumPages()
        MsgBox sName02 + " has " + CStr(vAnzahl02) + " pages and is open."
    End If
    If Doc03.Open(sPfad03) Then
        sName03 = Doc03.GetFileName()
        vAnzahl03 = Doc03.GetNumPages()
        MsgBox sName03 + " has " + CStr(vAnzahl03) + " pages and is open."
    End If
    
    If Doc01.InsertPages(vAnzahl01, Doc02, 0, vAnzahl02, 0) = False Then
        MsgBox "Document not inserted"

    Else
        MsgBox "Document inserted"
    End If
    
    If Doc01.Save(PDSaveFull, sPfad00) = False Then
        MsgBox "Document not saved"
    Else
        MsgBox "Document saved under " + sPfad00
    End If
    
    '------------------------
    Doc01.Close
    Doc02.Close
    Doc03.Close
    Aapp.Exit
    Set Aapp = Nothing
    Set Doc03 = Nothing
    Set Doc02 = Nothing
    Set Doc01 = Nothing
End Sub